According to this study conducted on 568 women, smoking before pregnancy could leave irreversible marks on the placenta.
Pregnancy and tobacco do not mix well, it is therefore not recommended for pregnant women to smoke during pregnancy. But according to this study carried out by the team from Inserm, CNRS and Université Grenoble Alpes, tobacco consumption can have irreversible consequences on the placenta "Even when it is stopped before pregnancy", is it stated in the British journal BMC Medecinde.
To arrive at such results, the researchers analyzed the placental DNA of 568 women. By the time the mother had smoked during the three months preceding her pregnancy (taking care to stop during the pregnancy), the study finds "epigenetic changes (DNA methylation) that can have consequences" on the course of pregnancy. "Although tobacco use during pregnancy has been shown to have many negative consequences for the health of mother and child, the mechanisms involved are still poorly understood," indicates the study. "The impact of pre-pregnancy tobacco exposure on placental DNA methylation has so far not been studied."
Risks to the fetus
This study grouped together several categories of women: non-smokers, former smokers who quit smoking three months before pregnancy and finally, smokers who smoked before and during pregnancy. According to the results, tobacco may also be linked to an epigenetic modification which results in the modification of the functioning of a cell, depending on its environment. "Previous studies have linked tobacco use during pregnancy to alterations in DNA methylation", explain the researchers, this "in the blood of the umbilical cord and in the cells of the placenta". Gold "the latter plays a crucial role in the development of the fetus, while remaining vulnerable to many chemical compounds".
Consequences on the child's subsequent health
The consumption of tobacco was already discouraged by the High Authority of Health, during pregnancy, because it increases the risk "pregnancy accidents such as retroplacental hematomas and low inserted placentas, intrauterine growth retardation, prematurity, sudden infant death and increased overall consumption of care in early childhood."
But according to this new study, the regions affected by past or present tobacco consumption are "Located on genes known to have an important role in the development of the fetus". So this discovery "suggests the existence of an epigenetic memory of exposure to tobacco", explains Inserm researcher Johanna Lepeule, who led this work.
Further studies on pregnancy and smoking are expected to see if the health of the child could be impacted.